1. Technical Field
The present invention relates to an apparatus which controls a device bay coupled to a computer system, and more particularly to an apparatus controlling peripheral devices mounted in a device bay which is coupled to a computer system.
2. Related Art
Computer systems are information handling systems that are utilized by many individuals and businesses today. A computer system can be defined as a microcomputer that includes a central processing unit (CPU), a volatile memory, a non-volatile memory such as read only memory (ROM), a display monitor, a keyboard, a mouse or other input device such as a trackball, a floppy diskette drive, a compact disc-read only memory (CD-ROM) drive, a modem, a hard disk storage device, and a printer. A computer system's main board, which is a printed circuit board known as a motherboard, is used to electrically connect these components together. A computer system can be a desktop computer, a portable computer, or other type of computer.
The central processing unit is of ten described as a microprocessor. The microprocessor is an electronic component having internal logic circuitry handling most, if not all, the data processing in the computer system. The internal logic circuitry of microprocessors is typically divided into three functional parts known as the input/output (I/O) unit, the control unit, and the arithmetic-logic unit (ALU). These three functional parts interact together and determine the power and performance of the microprocessor. The combination of the control unit and the arithmetic-logic unit can be referred to as the central processing unit. Also, the combination of the input/output unit, the control unit, and the arithmetic-logic unit can be referred to as the central processing unit.
One example of non-volatile memory is read only memory (ROM). Information stored in non-volatile memory can remain unchanged even when there is a power failure. The information stored in non-volatile memory will stay there until it is changed. Read only memory is used to store important information such as instructions for the central processing unit. There are different types of read only memory including electrically-erasable-programmable-read-only-memory (EEPROM) chip and flash-read-only-memory (flash-ROM). The flash-ROM can also be referred to as flash memory.
Computer systems include a basic input output system (BIOS) which is an especially important program stored in read only memory. The basic input output system tests a computer every time the computer is powered on. The basic input output system can allocate a computer system's resources automatically, making adjustments needed to accommodate new hardware. Also, the basic input output system governs how system board components interact.
When the computer system is powered on, the basic input output system immediately takes control of the computer system and its components. The first duty of the basic input output system is to perform a series of diagnostic routines called the power on self test (POST) routine, which ensures that every part of the computer system's hardware is functioning properly.
Consider a booting operation for a computer system using Microsof t Windows 95 as the operating system. First, a user starts the booting process by turning on a power switch to supply power to the computer system. Next, a basic input output system (BIOS) executes a power on self test (POST) to test and initialize the computer system's components. The basic input output system is software embedded on an integrated circuit located on the computer system's main board. The basic input output system also handles low-level input/output to various peripheral devices connected to the computer system. The power on selftest is the part of the basic input output system that takes control immediately after the computer is turned on. The power on self test initializes the computer hardware so that an operating system can be booted (loaded). When the power on selftest procedure is finished, a plug and play operation is executed if it is determined that all hardware is operating normally. A specification prepared by Microsoft and Intel that presents a mechanism to provide automatic configuration capability to Industry Standard Architecture (ISA) cards thus enabling full Plug and Play in the computer is dated May 5, 1994 and is entitled, "Plug and Play ISA Specification, Version 1.0a." During the plug and play operation, the entire computer system is scanned for new hardware.
The plug and play operation is executed every time that the computer system is booted. Now the plug and play operation shall be described in detail. At first, a configuration manager, which manages the plug and play operation, checks to determine whether a bus is being used. That is, a bus enumerator, which is a special driver managing a bus, builds a database by gathering information on peripheral devices. Next, the configuration manager uses the database built by the bus enumerator to build a hardware tree structure and stores the hardware tree structure in a memory. The hardware tree structure indicates the composition of the hardware being used in the computer system.
Subsequently, the configuration manager operates drivers of each peripheral device indicated in the hardware tree structure. After the drivers of each peripheral device are operated, a resource arbitrator, which resolves conflicts among system resources, distributes system resources to each peripheral device. Here, system resources include interrupt request lines (IRQs), input/output port addresses, memory addresses, direct memory access (DMA) channels, and more.
Lastly, the configuration manager transmits information to the bus enumerator regarding details of the distribution of the system resources. The bus enumerator transmits information regarding allowed system resources to each peripheral device connected to the bus, thereby enabling the user to utilize the peripheral devices.
Next, when the execution of the plug and play operation is completed, system files used by the Microsoft Windows 95 operating system are executed to complete the booting process of the computer system. Then the booting process of the computer system is complete.
Unfortunately, the booting process can require a substantial amount of time, due in part to the time required for the basic input output system routine and the power on self test, in addition to the plug and play operation. In the above booting operation of the computer system, because the plug and play operation is performed every time the computer system is booted, regardless of whether any new hardware has been added to the computer system, the booting time can be lengthy.
A computer system has peripheral devices connected, such as a monitor and keyboard. A user might want to use additional peripheral devices, such as a mouse, modem, printer, and scanner. When a user tries to use multiple peripheral devices with a computer, it can be difficult to connect them since each peripheral typically has a unique type of connector. The user must carefully match the plug from each peripheral with a corresponding connector on the computer due to all the different connector types. Also, it can be difficult to configure the computer to communicate with all the peripheral devices due to the fact that some peripheral devices require unique types of hardware and software.
To solve the above described problems, a universal serial bus (USB) system has been developed. The universal serial bus is a basic system for connecting peripheral devices to a computer. Peripheral devices connected to a universal serial bus system are also referred to as universal serial bus peripheral devices. All USB devices are compatible with standard USB cables and standard USB connectors in order to simplify the process of connecting devices to a computer system.
A keyboard or monitor can be directly connected to a computer or a universal serial bus within the computer. Other peripheral devices can be easily connected to the computer with the use of an expanded hub built into the keyboard or monitor, or even via an independent universal serial bus. The expanded hub offers additional connection sockets, and can be connected in a hierarchical tree form. Peripheral devices may be located close to each other or can be located several meters from each other, with the use of a universal serial bus hub.
A universal serial bus is able to connect a total of 127 USB devices to one computer. The operating voltage transmitted through the universal serial bus is limited to 5 volts. Thus, peripherals connected on a universal serial bus are limited in the amount of power they can consume. A rapid data transmission rate of 12 megabits per second on the universal serial bus is one of the advantageous features of the universal serial bus.
The major advantages of the universal serial bus include the simplicity and convenience of attaching and detaching peripheral devices to the computer. The universal serial bus detects whether a device is added or removed when related information is offered from a computer. The USB devices can be added to a computer system or removed from a computer system while the computer system is on, unlike non-USB configurations, thus eliminating the need for a reboot of the computer system.
Recently, as a new type of computer environment such as a multi-media computer or home network and a new communication environment focusing on a computer gather strength, peripheral equipments have been rapidly increased which are subject to be controlled by the computer.
Accordingly, in consideration that the current 1:1 connecting way of computer and peripheral equipments has reached a saturation condition in view of extensity of peripheral equipments, a new connecting way between computer and peripheral equipments has been contrived to be sought, led by business sectors related to computer, telephone and monitor.
Resultantly, a universal serial bus (hereinafter, termed as `USB`) standard for transmitting a middle and low speed data and an IEEE1394 standard for transmitting a high speed data come front as a new communication protocol for the computer, while a device bay employing the USB and the IEEE1394 is considered to be taken as a new connecting medium between the computer and the peripheral equipments. The IEEE 1394 standard was developed in conjunction with the Institute of Electrical and Electronics Engineers, Inc.
Namely, the USB and the IEEE1394 are new communication protocol with a notion of hot plugging or hot plug-and-play which are being supported by the business sector of a personal computer system or a computer system, a telephone and a monitor relevance.
The main reason of the advent of the USB and the IEEE1394 would be based on the fact that, faced with the situation that various peripheral equipment attached to a computer system are increased according to an increase of applied programs, it needs to overcome such limited situation that the computer system has to cover, for which the connectors of peripheral equipments in different shapes need to fit, to thereby attain a convenience in user's computer system operation.
The USB is applied to the middle and low speed equipment of which data transmitting speed is below 12 megabits per second (mbps) such as various modem, printer, joystick, mouse, key board and scanner. The IEEE1394 is applied to a high speed equipment of which data transmitting speed is around 100-400 megabits per second (mbps) such as a digital camera, video cassette tape recorder, optical disk reproducer.
The device bay system generally refers to a system which is capable of inserting and removing device without opening chassis of the main body of the computer system in case that a user desires to add a device such as a peripheral equipment of computer system or upgrade a function.
That is, the device bay system signifies a system which has the same notion as a video cassette tape recorder (VCR) so that the device of a computer system can be inserted or removed like a video tape is inserted or withdrawn into and out from a video cassette recorder.
The device bay can be inserted into the computer system or may exist separately.
For accomplishing the function, the device bay system is subject to give and take data and control signal and power by using the IEEE1394 and the USB as a communication means between the device and the computer system.
Accordingly, future users will be able to use any multi-media environmental peripheral equipments by connecting them to the computer system by using the USB, the IEEE1394, and the device bay even without any advance knowledge.
Meanwhile, in order to control the device bay, a device bay controller including the IEEE1394 and the USB interface is required.
I have found that there is a need for an apparatus to effectively and conveniently control a device in a device bay coupled to a computer system.